This invention relates to an electronic musical instrument, more particularly to an electronic musical instrument which produces musical tones of the highest or lowest tone pitch among the depressed keys.
In an electronic musical instrument, usually an accompaniment is played in a lower tone range (a lower keyboard), while a melody is played in a higher tone range (an upper keyboard). However, to emphasize the melody performance it has already been proposed to detect, for example, the highest pitch among the depressed keys and to produce the highest pitch tone with a tone color different from that of a main musical tone producing system by a special musical tone producing system different from the main musical tone producing system, as disclosed for example in a copending U.S. patent application Ser. No. 114,733 filed on Jan. 24, 1980 under a title of "Electronic Musical Instrument with Intermanual Performance Faculty". With this electronic musical instrument, while the melody performance is continued (at least one key is being depressed for the melody), the highest tone pitch of the melody performance tones can be produced by a special musical tone generating system with a tone color different from that of a main musical tone generating system. The melody performance tone is emphasized to provide a special effect. However, when the melody performance is momentarily interrupted (i.e. the moment when the melody is at a rest and no key is being depressed for the melody) with the accompaniment performance being done in the lower tone range, the highest tone pitch detected is the highest tone pitch among the accompaniment keys with the result that this highest tone pitch of the accompaniment performance tones is now produced by the special musical tone generating system. Accordingly, when the melody performance is momentarily interrupted, the musical tone generated by the special musical tone generating system is abruptly transferred to the accompaniment note thus producing an extremely unnatural progression.